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George BM

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Posts posted by George BM

  1. Take this for what it's worth, which may not be much, but IAD may have managed to sneak in a 90F today.

    Forecast high for today was 84F...

    No I'm not trying to imply that IAD will may 104F on Tuesday... They won't. :lol:

    They'll probably at least get into the upper half of the 90s... as forecasted anyway.

  2. Forecast Discussion

    Thursday, September 14, 2023 3:28PM EDT

    Our most significant and dangerous flash flood threat in more than 50 years will begin by this evening. Through Monday parts of the region may see more than half-a-years’ worth of rainfall.

    A Flash Flood Watch is in effect for the entire Washington/Baltimore Metropolitan region from 6PM this evening through Saturday though this will almost certainly end up being extended through at least Monday as forecast details for Sunday and Monday become clearer.

    With a near record strong WAR, a deep trough over the Ohio Valley and moisture from Margot streaming north from the Caribbean and western Atlantic east of Florida, Pwats will rise to the 2.25”-2.5”+ range from this evening through the beginning of next week. Clusters and trains of tropical downpours/storms will move north over the region at all times of the day. With limited sunshine and high moisture content temperatures will probably only vary by about 5-10F from daytime highs to nighttime lows (Low/mid 80s and mid/upper 70s respectively). Dewpoints will remain in the mid/upper 70s throughout the period. As far as severe weather goes there will be a daily threat of gusty winds and even a brief tornado or two especially with any transient supercells given CAPE values of 1500+ J/kg and effective SRH of 150-200 m2/s2. Lack of downdraft CAPE will prevent a bigger wind threat with storms though there may be a couple of mesovort maxes that move from south to north over the region over the next couple of days which may enhance both deep-layer and low-level shear leading to a locally higher risk of a brief tornadic supercell as well as bowing segments allowing for damaging/near-severe wind gusts and a QLCS tornado threat.

    The main threat by far, however, will be the very heavy rainfall rates with these downpours and storms. Given the aforementioned Pwats and CAPE any location that gets under a band of storms that trains over the area for an extended period of time may receive several inches of rain within a few hours leading to major flash flooding. Even areas that don’t get stuck under a train of convection as frequently if at all will see many individual storms or clusters over the next couple of days resulting in several inches of rain and flooding concerns. All of the above does not even account for when Margot will finally move north into the region by the Sunday PM/ Monday AM timeframe. More on that below.

    Models are coming into much better agreement that by sometime Sunday Margot will make landfall along the Carolina coastline being pulled north fairly rapidly by the strong ridge of high pressure to the east and deep trough of low pressure to the west. While the exact track and timing of the center are still being ironed out, as this is still 3 days away from occurring, it’s now looking very likely that at least a majority of the Baltimore/Washington region may experience significant impacts from Margot. Ahead of Margot on Sunday the low-level shear that will be with us through the weekend will further increase leading to a higher likelihood of tornadic supercells. As the center approaches and moves over the region a solid shield of heavy rain will move through leading to an additional several inches of rain. The biggest uncertainty that remains with Margot is how strong the tropical system will be at landfall along the Carolina coast as anything ranging from a tropical storm to, in the worst-case scenario, a major hurricane is plausible. This will determine the difference between getting several inches of rain with gusty winds Sunday into Monday OR damaging to hurricane-force wind gusts teaming up with the heavy tropical rains leading to widespread tree and structural damage.

    We will continue to monitor this potentially catastrophic situation with frequent updates over the next several days.

     

    Forecaster Wannabe: George BM

    • Like 7
    • Haha 1
    • Weenie 1
  3. 19 minutes ago, PrinceFrederickWx said:

    The 180 degree turn is what I found so crazy, not the hitting Nova Scotia part. 

    Oh I know... it's just that it made all those turns just to hit both Bermuda and Nova Scotia. Usually they just go roughly due north between the two locations.

  4. 4 minutes ago, PrinceFrederickWx said:

    No one commented on the hilarious 6z GFS track? Does a 180 out at sea, looks like its about to come crashing back into Delaware, then says "nah, I'll just hit Nova Scotia" :lol:

    I mean Bermuda and Nova Scotia have been tropical system magnets in recent years so... :P

  5. 5 minutes ago, gymengineer said:

    9 mb pressure drop (965 w/22 kt wind) in a little less than 2 hours.

    It's actually 968mb at the surface on that sonde... there's just no wind data at the very surface for some reason... so probably good for 967/966mb.

  6. 39 minutes ago, WxWatcher007 said:

    This is WxWatcher007 reporting live from Chiefland, FL, just inland from Cedar Key. We have a hurricane warning here and folks are taking the storm seriously. The forecast for the center is very tricky even now, as some models have been trending westward toward a near direct hit of Tallahassee while others are further east down to Cedar Key. The parallel track along the west coast of Florida makes this hard. I am hedging east right now, but am prepared to move north if necessary this evening. Will monitor trends. 

    As is usually the case, my friend @MillvilleWx is in communication with me, and this time I'm grateful to have @ORH_wxman supporting as well. If I lose power and internet, I'll be in touch with them so that everyone here knows I'm ok. 

    Driving in last night there was a wicked storm to my south. Perhaps a preview...

    giphy.gif

    Have fun!... obviously ditto to what Mappy said above as well. :thumbsup:

  7. 1 hour ago, Mrs.J said:

    My parents are now under a mandatory evacuation in Manatee County for Level A. I think they will be heading to my sisters in Atlanta like last year. 

    Best of luck to your parents.

    • Like 2
  8. 000
    WTNT65 KNHC 271513
    TCUAT5
    
    Tropical Storm Idalia Tropical Cyclone Update
    NWS National Hurricane Center Miami FL       AL102023
    1015 AM CDT Sun Aug 27 2023
    
    
    ...DEPRESSION STRENGTHENS TO A TROPICAL STORM...
    
    Observations from a NOAA Hurricane Hunter aircraft indicate that 
    Tropical Depression Ten has strengthened into Tropical Storm Idalia.
    The maximum winds are estimated to be 40 mph (65 km/h) with higher
    gusts.
    
    SUMMARY OF 1015 AM CDT...1515 UTC...INFORMATION
    ---------------------------------------------------
    LOCATION...19.9N 85.8W
    ABOUT 80 MI...135 KM ESE OF COZUMEL MEXICO
    MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
    PRESENT MOVEMENT...E OR 90 DEGREES AT 2 MPH...4 KM/H
    MINIMUM CENTRAL PRESSURE...996 MB...29.41 INCHES
    
    $$
    Forecaster Pasch
    • Like 3
  9. This morning the air was uncomfortable for serious running, pre-dawn. 

    Now it's only 5-7F warmer than it was during the 5am hour w/ dewpoints nearly 20F lower w/ the breeze making it feel like September.

    Overall, a fairly similar day to this past Friday.

    Currently IAD at 82/49.

  10. 2 hours ago, WxWatcher007 said:

    Should have Franklin at 5pm with Invest 90L. Recon finding TS winds and I think enough of a closed circulation. 

    Yeap.

     

    000
    WTNT33 KNHC 202053
    TCPAT3
    
    BULLETIN
    Tropical Storm Franklin Advisory Number   1
    NWS National Hurricane Center Miami FL       AL082023
    500 PM AST Sun Aug 20 2023
    
    ...TROPICAL STORM FRANKLIN FORMS IN THE CARIBBEAN SEA..
    ...TROPICAL STORM WATCHES ISSUED FOR THE SOUTH COAST OF HAITI AND
    THE DOMINICAN REPUBLIC...
    
    
    SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
    ----------------------------------------------
    LOCATION...14.6N 67.1W
    ABOUT 270 MI...435 KM SSE OF ISLA SAONA DOMINICAN REPUBLIC
    ABOUT 270 MI...435 KM SSW OF SAN JUAN PUERTO RICO
    MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
    PRESENT MOVEMENT...WNW OR 290 DEGREES AT 14 MPH...22 KM/H
    MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

    .....

    • Like 1
  11. 1 hour ago, CAPE said:

    After 2 weeks away was thinking of doing a bit of mowing (as nice as it feels out now), but a couple drinks in + weed, eff that.  With the mixing/lowering dews, should be prime mowing weather around 6am- about 60 f.

    That's one advantage of living relatively isolated from others.

    • Like 3
  12. This got lost in the severe tracking but that 12z GFS run for Friday the 18th was total lolism. Temps in the mid 80s+ at the crack of dawn w/ 110+F highs across the region during the afternoon. :lol:

    OBVIOUSLY 18z is more realistic with no Desert SW-like heat.

    • Haha 1
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